[en] This work is a retrospective study of 75 patients with non small cell lung cancer irradiated postoperatively. The overall 5-year survival rate of 28% was achieved. The extent of surgical resection and post-surgical (pathologic-pTNM) staging are two significant prognostic factors. The best results (70% of 5-year survival) was obtained in patients without mediastinal metastases, irradiated for microscopic residual tumour on the resected margin. Postoperative irradiation was ineffective in the group of patients with mediastinal lymph node involvement and with microscopical incomplete surgery